This invention relates to a wire stock cooling tube and more particularly a wire stock cooling tube especially suitable for continuously cooling hot rolled wire stocks.
Where a hot rolled wire stock is cooled by causing it to run though cooling liquid the cooling liquid in contact with the surface of the wire stock forms a film of vapor and when the cooling liquid becomes a boiling heat state conduction is greatly reduced thereby impairing the cooling effect. Such boiling can be prevented by increasing the pressure of the cooling liquid.
In a prior art cooling tube for a wire stock the interior of the cooling tube is divided into a plurality of sections by means of partition members each provided with a perforation having a diameter slightly larger than that of the wire stock, and supply and discharge of the cooling liquid are made for respective sections for the purpose of increasing the liquid pressure in respective sections.
The perforation of each partition member has a circular cross-sectional configuration with the diameter gradually decreasing in the direction of running of the wire stock.
A hot rolling mill for reducing the diameter of a wire stock comprises a plurality of spaced mill stands with their direction of rolling of adjacent stands 90.degree. dephased. Accordingly, the roll pair of the first mill stand rolls the wire stock to have an oval cross-section and the roll pair of the second stand rolls the wire stock in the direction of the major axis of the oval thus changing the cross-section of the wire stock into circular having a smaller diameter. Succeeding stands repeat rolling into oval and circular cross-sections until finally a wire stock having a desired diameter and circular cross-sectional configuration is produced.
In the hot rolling mill described above, change of the product diameter is done in the following manner. Where it is desired to decrease the diameter of the product, among a plurality of roll pairs, roll pairs not have been participated in the rolling operation are brought into operation. In order to avoid not to apply an excessively large load on a wire feed or take-up motor, the participation of such idle roll pairs should be made pair after pair while adjusting the wire take up speed. On the other hand, where it is desired to increase the product diameter, a desired number of roll pairs now participating in the rolling operation is rendered idle, again pair after pair. For this reason, when the diameter of the product is changed, it is inevitable to produce transition portions for the product where the cross-sectional configuration is oval.